1. Field of the Invention
The present invention relates to a photographing apparatus and method. More particularly, the present invention relates to a photographing apparatus and method employing multiple digital zoom devices that are used to achieve a desired magnification.
2. Description of the Related Art
A photographing apparatus for photographing a still image or moving picture performs a zoom process to magnify and photograph an object located at a far position. The zoom process includes an optical zoom processing method and a digital zoom processing method. The optical zoom processing method enables enlargement photographing of an object by adjusting the positions of lenses. The digital zoom processing method enables enlargement photographing of an object by electronically magnifying an image photographed through a lens. Zoom processing technology according to the optical zoom processing method and the digital zoom processing method is disclosed, for example, in Japanese Patent Publication No. 2006-217577.
The digital zoom processing method includes a first method of magnifying an image using a pipe line (Mode 1), and a second method of temporarily storing an image and magnifying the stored image (Mode 2).
FIG. 5 is a block diagram illustrating the configuration of a conventional photographing apparatus. Referring to FIG. 5, a photographing apparatus 10 according to the conventional technology includes a photographing unit 11, a pre-processing unit 12, an interpolation unit 13, a magnification unit 14, a memory 15, a memory controller 16, an image compression unit 17, a recording unit 18, an external recording I/F (interface) 19, and a display portion 20.
In Mode 1, the photographed image data is directly magnified. That is, in Mode 1, for the image data photographed by the photographing unit 11, the pre-processing unit 12 generates evaluation values such as auto exposure (AE), auto focus (AF), and auto white balance (AWB), the interpolation unit 13 interpolates the photographed image data, and the magnification unit 14 magnifies the image data.
In Mode 2, the photographed image data is stored in the memory 15 and a portion needed (e.g., only that portion needed) for zoom processing is extracted and magnified. That is, in Mode 2, for the image data photographed by the photographed unit 11, the pre-processing unit 12 generates evaluation values such as auto exposure (AE), auto focus (AF), and auto white balance (AWB). When the evaluation values are generated, they are temporarily stored in the memory 15 by the memory controller 16. The image data corresponding to a range needed for the zoom processing (e.g., only that image data) is read out from the memory 15. The read-out image data is input to the interpolation unit 13 so that the image data is interpolated. The interpolated image data is magnified by the magnification unit 14.
However, in Mode 1, a high speed processing clock proportional to the magnification power is needed. That is, to obtain an N-times magnified image, an N-times processing clock is needed. Thus, to obtain a high magnification image, consumption power increases and a large-scale logical circuit operating at a high speed clock is needed.
FIG. 6 illustrates the digital zoom processing time of the operation of the photographing apparatus shown in FIG. 5. In Mode 1, when image data is magnified twice, for example, while vertical processing time is reduced to ½, horizontal processing time is not changed. Thus, to magnify image data twice, the magnification processing needs to be performed with twice greater processing capability than before magnification. Since in Mode 1, N-times greater processing capability than before magnification is needed to perform N-times greater processing after magnification, as a magnification power increases, the processing capability needed for the photographing apparatus therefore proportionally increases. As the processing capability increases, a high speed clock is needed, and thus, the size and complexity of the circuit increases.
In Mode 2, as the magnification power increases, the range of the image that is temporarily stored can be decreased. Thus, when the magnification power increases, the amount of writing or reading out decreases so that the overall process can be efficiently performed. However, when the magnification power decreases, the overall process becomes inefficient because an image in a range that is almost the same as that of the photographed image is written or read out.